Apparatus for forming lined concrete pipe



Dec. 29, 1942. R. P. PETERSEN APPARATUS FOR FORMING LINED CONCRETE PIPE Filed April 23, 1941 2 Sheets-Sheet l Dec. 29, 1942. PETERSEN 2,306,496

APPARATUS FOR FORMING LINED CONCRETE PIPE Filed April 23, 1941- 2 Sheets-Sheet 2 Wm Fig.6.

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. Mt p/Qafiv/um Patented Dec. 29, 1942 APPARATUS FOR FORMING LINED CONCRETE PIPE Robert P. Petersen, Philadelphia, Pa., assignor to Concrete Products Company of America, Philadelphia, Pa., a corporation of Pennsylvania Application April 23, 1941, Serial No. 389,989

Claims.

This invention pertains to a reinforced concrete vitrified pipe specifically designed for use as sewer pipe, or aqueduct and to the method and apparatus for producing it.

Previously, concrete sewers and aqueducts, requiring a vitrified inner lining, were first constructed as a concrete sewer 'or aqueduct and the vitrified liner installed as a secondary operation to the completed construction or the process merely reversed; whereas the present finished product completes such a sewer or aqueduct in one operation due to the unitary reinforced concrete vitrified pipe resulting from the process of manufacture herein described.

Heretofore concrete pipe with liners of various types has been produced. The usual'method of producing this type of lined pipe is to cast concrete about the liner, with or without rotation of the liner, the liner being surrounded by a suitable outer form. This method produces a twopiece pipe composed of the liner and the outer concrete cylinder, in effect two pipes in one.

This type of pipe has many disadvantages.- Due to imperfect bonding and honeycombing between the lining and the concrete, cracks and voids are formed therebetween allowing penetration of corrosive chemical substances which results in a comparatively rapid deterioration of the structure, cracking of the liner and separation thereof from the concrete. Pipes of this type have a relatively short andinefiicient life. Their deterioration causes seepage of sewage and gas which endangers health and life in the localities where they are used. Further, due to the variable thickness of the concrete outer layer and the resulting imperfect alignment of the liners between the pipe sections, there is caused obstructions to the passage of matter through the pipes, stoppage and the resultant seepage and deteriorating action.

The improved pipe forming the subject matter of this invention obviates many of these defects. It comprises broadly an integral vitrified clay liner, a. preformed steel reinforcing member and an integral coating of concrete, united in such a manner as to produce, not a. two-piece pipe, but a unitary and homogeneous structure of increased and uniform strength and adapted'to provide perfect joints between the liner of adjacent sections which are impervious to the deteriorating action of corrosives carried. by it. The invention further contemplates the production of such ai pipe which is completely uniform in thickness and strength.

One of the objects of the invention, therefore, is

Another object of the invention is to provide an improved vitrified clay liner which is so formed on its outer surface as to provide a perfect bond between the concrete and the liner.

Another object is to provide'an improved bell structure for such pipe which will eliminate stoppage and seepage at the joints thereof. 1

Another object is to provide improved reinforcing by means of a mandrel already patented.

Other and further objects of this invention will become apparent as the specification proceeds. 7

Referring to the drawings:

Fig. 1 is a side elevation, partially in section, of the improved apparatus for forming the lined pipe showing the liner, reinforcing member and outer shell in position on the table, and the core partially in place within the liner;

, Fig. 2 is a horizontal section of the apparatus showing the core and spring rollers in position inside the clay liner, the reinforcing steel member on the liner and the outer steel form in position about the liner, subsequent to pouring the concrete;

Fig. 3 is a transverse section of the steel reinforcing means;

Fig. 4 is a side elevation of the steel reinforcing means;

Fig; 5 is a section of the bell mouth of the pipe showing the structure carried at the upper extremity of the core to form said mouth; h

Fi 6 is a transverse section of the vitrified clay liner showing the vertical fiutings on its exterior and the smooth interior surface;

Fig. 7 is a side elevation of the liner;

Fig. 8 is a transverse section of the liner, showing the steel reinforcing means in position there'- on; and

Fig. 9 is a longitudinal section of the liner with the steel reinforcing means applied thereon.

In Fig. 1, l indicates a suitable vitrified clay liner which is preferably a hollow cylinder with a smooth interior surface and a longitudinally fluted and roughened exterior surface. liner is preformed in a suitable baking operation. Its

interior surface is glazed and its fluted exterior is preferably roughened by the provision of suitable corrugations or projections on the interior of the baking mold. It may be of any desired thickness, depending upon the diameter of the pipe being formed.

Applied about liner I is reinforcing member 2 which is preformed of steel wire on a mandrel which is already, patented. The reinforcing member is substantially helical in shape and of a diameter slightly larger than that of liner I. It is carefully preformed and closely fits liner I. The diameter of the steel wire may vary from No. 5 gauge to 00 gauge, depending upon the size of pipe being produced. Reinforcing member 2 preferably carries vertical rOds 2a designed to fit into the low points between the vertical flutings of the outer periphery of the liner designed to provide a means of exact spacing of spiral wire and to provide additional longitudinal strength.

Surrounding liner I and reinforcing member 2,

and at a desired distance therefrom, is outer form or shell 3, which is preferably made of steel and which may be in one or more sections, as desired. Preferably outer shell 3 is made in two sections which may be bolted or otherwise ailixed together,

as shown in Fig. 2. The space between the liner I and shell 3 is filled with concrete 4 as hereinafter described, after which the form or shell is removed.

In making a section of pipe as shown in Fig. l, liner I and outer shell '3 are suitably supported in fixed relation to each other in a vertical position on a suitably rotating table 5, which may be of any suitable material and shape and which is suitably mounted on shaft 1 for rotation about its center. Rotation may be imparted to table 5 by any suitable means, as for example, by means of pinion 8 carried by shaft 9, which meshes with a suitable ring gearing III carried by the table 5 and concentric with the shaft I. Shaft 9 and pinion 8 may be driven from any suitable source of power so that the assembly of the liner I, reinforcing member 2 and shell 3 is rotated as a unit while the concrete 4 is being poured.

Cor I0 is illustrated in position above table 5 and partially within liner I. Core I0 is preferably constructed of steel and. is preferably hollow to reduce its weight. It is cylindrical in shape and of substantially the same length as the section of pipe being formed. As illustrated, it is so disposed as to be coaxial with the shaft I. Affixed at the upper end of core II] is a suitable shaft I I, preferably made of steel, which is designed slidably to engage fixed hearing or bracket I2 so that thecore can be raised and lowered in any suitable manner.

Spring guide roller units are illustrated disposed about the upper and lower peripheries of core Ill. These units in the form shown comprise rollers I4 mounted for rotation in bearing members I5 that are pivoted on plates It, the latter being slidable on studs I'I. Suitable coil springs I8 are disposed about studs I'I between plates I6 and brackets I9 in such fashion as to resist inward movement of plates It on studs I'I. As illustrated, brackets I9 are suitably affixed to core III by bolts. Spring guide rollers I4 are designed to extend outwardly from the surface of core II] to a distance substantially one half an inch greater than the interior diameter of clay liner I. They are preferably disposed at 90 intervals about the outer periphery of core I0. Since rollers I4 are so mounted on plates I6 as to be free swinging, they will normally assume a vertical position, as illustrated in Fig. 1. I

Fig. 2 discloses core I0 in position within liner I and outer shell 3. Rollers l4 are shown in con- 75 tact with the inner wall of liner I and springs I8 are shown in compressed condition. It will be noted that the free swinging rollers I4 have assumed a horizontal position, imparted to them by the rotation of liner I.

Also shown in Fig. 1 are tamper sticks 20 and 2| carrying suitable tamping heads 22 and 23. Tamper sticks 20 and 2I are operated in any suitable way as by means of suitable cams 24 and 25 driven by a shaft 26 which is rotatably mounted in fixed bearing 21. Tamper tick 2| is designed for the tamping of the body of the pipe and tamper stick 20 is designed to tamp the bell section of the pipe.

The concrete 4 is caused to flow freely into the space between liner I and outer shell 3, during rotation of the form. The concrete utilized depends upon the specifications for the particular pipe being formed. It is usually a rich mixture, for example, one part cement to two parts of sand and three of gravel.

In Figs. 3 and 4 the steel reinforcing member 2 is illustrated. This member is preferably composed of steel wire of from No. 5 gauge to 00 gauge and is accurately preformed ona mandrel, which has already been patented, to a diameter slightly greater than the external diameter of liner I. It will be noted that reinforcing member 2 is preferably made in the shape of a helix and carries at suitable intervals about its inner circumference vertical reinforcing rods 2a. Reinforcing rods 2a may be secured to the reinforcing member in any suitable manner, as by welding.

In Fig. 5 a form structure is illustrated in conjunction with core III for the formation of the bell at the upper end of the pipe structure. As illustrated, a suitable bell core member 28 is affixed at the upper extremity of core In as by bolts 30. Bell core member 28 is made substantially L-shaped and cooperates with vertical section 3a of outer shell 3 to form the bell at the upper end of the pipe section. Arm 29 is illustrated. Arm 29 is preferably afilxed to a suitable post beside the apparatus to hold core I0 stationary during rotation of the table. It will be further noted that liner I extends flush with the bottom surface of the bell. By providing a rubber gasket of from 1" to 2 in thickness about the interior of the bell an external sealed joint may be formed between the bell and the spigot end of the adjacent pipe section. The liners of adjacent sectionsabut tightly against each other and provide a perfect joint between the liners which eliminates obstructions and seepage, the liners and bell mouths of each section being accurately centered and the pipe sections when fitted to gether being truly coaxial.

In Figs. 6, '7, 8 and 9 the vitrified clay liner I is illustrated. This liner is composed of vitrified clay, its interior and exterior surfaces are glazed and its-exterior surface is so molded as to be longitudinally fluted as indicated at Ia. Flutings Ia are formed and equally spaced about the periphery of the liner and their outer surfaces are roughened to provide a more extensive bonding area for the concrete.

Fig. 8 shows a transverse section of clay liner I with reinforcing member 2 applied. thereon. It will be seen from this figure that the coils of reinforcing member 2 ride on the flutings Ia-of liner I and that vertical rods 20, register with the low points between the flutings. This arrangement, together with the concrete when properly cured, creates a completely unitary structure as a result of the configuration.

that the axis of the liner is in line with the axis of the shaft 1. Before the liner is placed upon the table, core member H) is in raised position to allow clearance for the placement of the liner.

With the liner in place outer shell 3 is placed on the table about the liner with its axis in line with the axis of shaft 7, the difference in diameter of the liner and shell providing a constant distance therebetween which depends upon the thickness of pipe desired. As before stated, shell 3 may be unitary or sectional, as desired. The proper positioning of the shell may be assured by the provision of a table 5.

With liner I and outer shell 3 in position the core I!) is lowered into liner I. As rollers M are free swinging they assume a vertical position upon contact with the interior wall of the liner and as the core is lowered into position, the springs I8 assuming a compression of approximately one half an inch. This compression results in a pressure of approximately 15 pounds per square inch being exerted by rollers I4 which holds them firmly against the inner wall of liner I.

When core member I!) is completely lowered within the liner rotation is imparted to table 5 through pinion 8 and shaft 9, the rollers swinging to a horizontal position, and thepouring operation is begun. As the concrete is being poured, the temper unit is brought into operation. Under these rotative and tamping actions an extremely close packing of the concrete between outer shell 3 and the fluted and roughened surfaces of liner I is produced.

As before stated, the axis of core I is concentric with the axis of liner I and table 5. Spring guide rollers I4 are compressed within liner I and bear thereagainst with pressures of approximately 15 pounds per square inch. It will therefore be seen that any irregularities in curvature in liner I will be compensated for as the liner rotates about the fixed core I I]. This produces an exact rotation of the liner about its .axis which results in the application of a precisely uniform layer of concrete over the liner. Any discrepancies in the inner diameter of the liner and any irregularities in its inner surface are compensated by the flexing of springs I8.

When the concrete is completely poured and the tamping operation completed rotation of table is stopped, core I0 is raised until it clears the top of the form, and thereafter the entire form is removed from table 5 and placed in the curing chambers. Subsequently, the outer steel shell 3 is removed and the pipe is left until it is completely cured.

Due to the fact that the concrete is poured during the rotation of the liner and the outer shell, and due to the fluted configuration of the outer surface of the liner and the method of applying the reinforcing means thereto, the concrete flows completely about the reinforcing steel through the low portions of the fluted surfaces. The tamping in conjunction with the rotative action results in packing a concrete of uniform density against the surfaces of the liner and eliminates voids in the concrete and between it and the liner. This takes care of bonding in the steel and results in a homogeneous and unitary final product.

suitable annular rim 6 on' The fiuting and roughening of the outer surfaceof the liner results in a greatly increased bonding area on the outer surface of the liner and produces an infrangi'ble and impervious union between the clay liner and the outer concrete coating.

One of the serious defects of cast concrete lined pipe in the past has been that, due to uneven thickness, voids and non-uniform density of the concrete, it was'much weaker in certain spots than in others. This resulted in cracking, distortion of the pipe and failure to carry a constant load. In the present process however, the core member ID and spring guide rollers I4 maintain liner I at all times in rotation exactly about its axis and in perfect vertical alignment with the outer shell during the rotation of the table. This results in a precisely uniform coating of concrete about all portions of the liner and produces a completely uniform final product whose strength is constant for all points on its surface. Moreover the pipe produced by this method has an exceptionally high ultimate strength, due to its novel construction and the fact that it is a homogeneous unit of uniform thickness and density. 7

Due to the accurate centering and alignment of the liner and'bell mouth, and the uniform thickness of the concrete, the liner of the spigot end 'meets the liner of the bell end at the base of the bell in a perfect joint, and stoppage and seepage are eliminated. This pipe combines the corrosive resisting qualities of vitrified clay pipe with the extra strength of reinforced concrete pipe in one unitary structure. The result is a pipe of exceedingly long life and unusual strength, giving perfect service under any condition of normal use.

The invention is susceptible of modification and changes in detail without departing from the spirit thereof. The particular construction and apparatus described above are by way of illustration only and are not intended to define the scope of the invention. Attention is directed to the appended claims for this purpose.

What is claimed is:

1. In an apparatus forforming lined concrete pipe, a table, means for rotating said table about a vertical axis, said table being adapted to support and rotate a pipe liner arranged coaxially therewith, an outer concrete-retaining shell on said table about said liner and arranged coaxially therewith, a core member adapted to fit within said liner coaxially therewith, means for relatively vertically moving said core member and table to bring the liner and core into operative position, and guides disposed about the periphery of said core member to maintain the alignment of said liner with respect to said outer shell during rotation of said table.

2. In an apparatus for forming lined concrete pipe, a table, means for rotating said table about a vertical axis, said table being adapted to support and rotate a pipe liner removably applied to said table and coaxial therewith, an outer shell removably applied to said table about said liner and coaxial therewith, a core adapted to fit withing said liner coaxially therewith, means for relatively vertically moving said core member and table to bring the liner and core into operative position, and resilient guide means disposed about the periphery of said core member to maintain the alignment of said liner with respect to said outer shell on said table.

3. In an apparatus for forming a lined pipe, a

table, means for rotating said table about a vertical axis, said table being adapted to support and rotate a pipe liner removably applied to said table and coaxial therewith, an outer shell removably applied to said table about said liner and coaxial therewith, a core member adapted to fit within said liner and coaxial therewith, means for relatively vertically moving said core member and table to bring the liner and core into operative position, spring-pressure guide rollers disposed about the periphery of said core member to maintain the alignment of said liner with respect to said outer shell during rotation of said table.

4. In an apparatus for forming a lined pipe, a table, means for rotating said table about a vertical axis, said table being adapted to support and rotate a pipe liner removably applied to said table and coaxial therewith, an outer shell removably applied to said table about said liner and coaxial therewith, a core member adapted to fit within said liner and coaxial therewith, means for relatively vertically moving said core memher and table to bring the liner and core into operative position, spring-pressure guide rollers spaced about the periphery of said core member adjacent the top and bottom thereof to maintain the alignment of said liner with respect to said outer shell during rotation of said table.

5. In an apparatus for forming a lined pipe, a table, means for rotating said table about a vertical axis, said table 'being adapted to support and rotate a pipe liner coaxial therewith, an outer concrete retaining shell removably applied to said table about said liner and coaxial therewith, a core member adapted to fit within said liner coaxially therewith, means for relatively vertically moving said core member and table to bring the liner and core into operative position, springpressure guide rollers disposed about the periphcry of said core member to maintain thealignment of said liner with respect to said outer shell during rotation of said table, and tampers disposed above said table for tamping concrete between the liner and shell.

ROBERT P. PETERSEN. 

